Speculation has been singularly fruitful as to what these markings on our next to nearest neighbor in space may mean. Each astronomer holds a different pet theory on the subject, and pooh-poohs those of all the others. Nevertheless, the most self-evident explanation from the markings themselves is probably the true one; namely, that in them we are looking upon the result of the work of some sort of intelligent beings. . . . The amazing blue network on Mars hints that one planet besides our own is actually inhabited now.
Percival LowellThat Mars is inhabited by beings of some sort or other we may consider as certain as it is uncertain what these beings may be.
Percival LowellIrrigation, unscientifically conducted, would not give us such truly wonderful mathematical fitness [as we observe in the Martian canals]. . . . A mind of no mean order would seem to have presided over the system we see-a mind certainly of considerably more comprehensiveness than that which presides over the various department of our own public works.
Percival LowellThere are celestial sights more dazzling, spectacles that inspire more awe, but to the thoughtful observer who is privileged to see them well, there is nothing in the sky so profoundly impressive as the canals of Mars. Fine lines and little gossamer filaments only, cobwebbing the face of the Martian disk, but threads to draw one's mind after them across the millions of miles of intervening void.
Percival Lowell